Effects of Castratiott in Insects 417 



by Intoshia kefersteini, of the brittle, star Amphiara squamata by 

 theorthonectid Rhopalura giardi and by a copepod (Fewkes '88), 

 ofthesnailsof the genera Paludina, Ly^mnaea and Planorbis by dis- 

 tome sporocysts (Distomum mihtare, retusum, etc.), of the crus- 

 tacean Cyclops tenuirostris by larval distomes (Herrick '83), 

 of the bumble bees (Bombus) by the extraordinary nematode 

 Sphaerularia bombi, and of the males of various North American 

 squirrels and chipmunks (Tamias lysteri,Sciurus hudsonius and 

 leucotis) by the bot-fly Cuterebra emasculator as described by 

 Fitch ('59), Riley and Howard ('89) and Osborn ('96). Among 

 plants Giard cites the castration of the fig by Blastophaga 

 grossorum, of Melandryum album (Lychnis dioica) by Ustilago 

 antherarum and various grasses by smuts, ergots, rusts, etc. 

 The case of Melandryum and Ustilago which was repeatedh' 

 studied by Giard('69, '87a, '88J, '89(2) bears a curious resemblance 

 to that of the male crab infested with Sacculina. The Melan- 

 dryum is "normally dioecious. The }oung flower is hermaphro- 

 dite but in certain individuals the ovaries abort, in others the 

 stamens remam rudmientar\ . When the parasitic fungus develops 

 on a male plant, it fructifies in the stamens, but when it falls on 

 a female plant, it seems at first as though it could not fructify 

 and that the infested plant must profit accordingly. But this is 

 not the case, for the plant develops its rudimentary stamens 

 completely in order to permit the fructification of the parasite, 

 just as the male Stenorhynchus enlarges its abdomen in order 

 to protect the Saccuhna fraissei." 



Castration frequently occurs in plants through petalody, pr 

 petalomania, /. e. the conversion of stamens or carpels into 

 petals, producing the well-known ""double" flowers. MoUiard 

 ('01) has produced petalody experimentally in Scabiosa colum- 

 baria by artificially infecting the plant with the nematode 

 Heterodera radicicola. And this investigator, Meehan ('00), 

 Giard ('02) and Cramer ('07) cite a number of observations 

 which indicate that petalody is often the result of infection of a 

 plant with root-fungi. Veuillemin ('07) has observed in Lonicera 

 infested with aphids a suppression of the carpels and a distinct 

 androgen y of a certain number of the flowers. 



